by Andrea Mandell, USA TODAY

by Andrea Mandell, USA TODAY

LOS ANGELES-There are bad days, and then there's the day Tammy is having.

Melissa McCarthy's all-American, Midwestern mess, Tammy, steamrolls into theaters Wednesday. Tammy's car is smoking, she's dead broke, her husband is a cheater and, in a rage, she burns every bridge she can find quitting her job at a fast food joint.

McCarthy may have had a few rough years working the improv scene starting out in New York, but, "I've never been like that," laughs McCarthy, who co-wrote Tammy with her husband Ben Falcone, who makes his directorial debut.

The couple have flown in from Budapest where McCarthy is headlining a new comedy, Spy. Their two young daughters, Vivian and Georgette, have tagged along, keeping the family unit together. "We travel as the circus tribe we are," says McCarthy, 43.

Tammy is a continuation of a line of characters McCarthy loves to play, chiefly "aggressive self pitying victims," especially those whose corrosive behavior digs them deeper into the abyss. "I'm always fascinated by those cycles that you can't pull yourself out of," says McCarthy, whose character holds up a burger joint (steals some pies) and hits the road with her booze-swilling grandmother (Susan Sarandon). "I love to want to root for somebody as they're falling down flat on their face, literally and emotionally."

It's also a homegrown tale, born in her kitchen. "Ben came downstairs five years ago, still bleary-eyed, hair all over the place and said, 'I think I'm going to write something where you take a road trip with your grandmother who's an alcoholic.' And I was like, 'Good morning.'"

True, Sarandon, 67, barely qualifies as grandmother-appropriate for McCarthy, but with the aid of some blurry math, Sarandon signed on. "I kind of like that she's an alcoholic," Sarandon, who trades her sultry looks for a curly white wig and prosthetic cankles. "It was very liberating to just accentuate every bad thing about you and not worry."

In real life, Sarandon will be bonafide grandmother soon, daughter Eva Amurri Martino is set to give birth to a baby girl. No 'Grandma' here though, she'll be called 'Honey.' "It's going to be really fun," she says. "And I know (Eva's) going to think I'm so much more brilliant than she ever knew when she starts to deal with having a child."

Melissa's messiest day

In real life, neither woman has much experience at being a bonifide mess. The closest McCarthy can come is when she first moved to Los Angeles, and was squatting in a friend's studio while juggling jobs at Starbucks and the YMCA.

Her lowest moment? She was answering phones at the YMCA when "I put a call through to someone and I think he picked up the wrong line and didn't want to talk to whoever was on the wrong line. He came running out and from the balcony started screaming at me, like, 'IF YOU DON'T KNOW HOW TO PUT A PHONE CALL THROUGHâ??"

"I don't know what happened but it was like all my Irish came out and took the top of my head off. And I went flying after him," McCarthy laughs. "I ran up the stairs, down the hallway, I threw open the doorâ?¦and I just screamed at him," indignant: 'HOW DARE YOU YELL AT ME.'"

Sarandon laughs. "I bet that guy is so proud of that story now, that Melissa McCarthy chewed him out. He's probably bragging about it."

A longtime partnership

McCarthy and Falcone, 40, met performing in the improv group, The Groundlings. McCarthy says he waited a year and a half to ask her out. "It was that weird thing, should we start dating? Because we're already best friends and we didn't want to ruin that," she says.

These days at home, "our favorite thing is watching Chopped with my girls," she says. "Vivi watches it like a full sporting event. She talks like, 'Oh, that's too much pepper. I think she's really trying with this sauce.'"

They remain as memorable on-screen (see: his Air Marshall trying to avoid her sexual advances in Bridesmaids) as off. What writing and producing and starring in their first joint feature really means is "we're getting lots of spreadsheets that are very difficult to read," says Falcone, chuckling. "But everyone seems pleased."

There's a new projects in the works, too: Falcone and McCarthy have teed up a new comedy for Universal. Plotline: One of the "wealthiest women in the world that loses everything to white collar crime and has to rebuild herself."